Final answer:
After executing the code snippets, the contents of R20 will first be 0x7A and then change to 0x75 following the EOR operation with R21.
Step-by-step explanation:
The student asks to Find the contents of R20 after each of these code snippets. (put answers in hex) LDI R20, B 0111 1010, LDI R21, 0x0f EOR R20, R21. This question is about assembly language programming, specifically involving loading immediate values into registers and performing a bitwise exclusive OR (EOR) operation. the first instruction 'LDI R20, B 0111 1010' loads the binary value 0111 1010 into register R20, which is equivalent to the hexadecimal value 0x7A. After this instruction, the contents of R20 will be 0x7A.
Next, 'LDI R21, 0x0F' loads the hexadecimal value 0x0F into register R21. Following this, 'EOR R20, R21' performs an exclusive OR operation between the contents of R20 and R21. The result of 0x7A EOR 0x0F is 0x75, so after this operation, the contents of R20 will be 0x75 in hexadecimal.